The use of compressible and expandable retention members, such as those utilizing balloons or cuffs, are well known in a wide variety of medical fields. For example, U.S. Pat. Nos. 3,640,282 and 3,799,173 disclose expandable and compressible foam-filled retention cuffs used on endotracheal tubes. U.S. Pat. Nos. 4,795,430 and 4,900,306 disclose the use of inflatable and compressible foam-filled retention balloons in percutaneous endoscopic gastrostomy tubes. Inflatable balloons carried on catheters also find clinical applications in angioplasty.
FIGS. 1 and 2 disclose a prior art retention member a in a fully expanded configuration. FIG. 1A discloses the same retention member in a fully collapsed configuration. The retention member may be an annular-shaped balloon member secured near a distal open end b of a percutaneous catheter, such as a gastrostomy tube c having a fluid lumen d. Typically, the retention member a is circumferentially secured solely to the outer surface of the tube c.
The retention member a may be expandable through a secondary lumen e, typically an air lumen. Further, an expansion chamber f of the retention member a may be substantially filled with a polyurethane foam g to urge retention member a to assume the expanded outer configuration. Foam g, however, is sufficiently compressible to permit the retention member a to assume the collapsed or deformed outer configuration shown in FIG. 1A.
One disadvantage of the structure of retention member a occurs upon collapse. As shown in FIG. 1A, because retention member a is circumferentially secured to the outer surface of tube c, upon collapse, the retention member a collapses around the outer diameter of the tube. As a result, the overall outer dimensions of the collapsed retention member a exceeds the outer diameter of the tube. This causes extraction and removal of the retention member a through the stoma to be more difficult and increases the risk of damage to the exit site of the stoma.
Hence, prior to the development of the present invention, a need existed for a pre-formed retention member capable of being in a collapsed state and used for percutaneous tubes and other internally anchored catheters which would overcome these and other problems.